Hearing system with at least one hearing instrument worn on the user's head and methods for operating such a hearing system

Abstract

Method for operating a hearing system (2) to assist the hearing ability of a user, comprising at least one hearing instrument (4) worn on the head, in particular in or on an ear of the user, - wherein a sound signal from the user's environment is received by means of at least two input transducers (6) of the hearing system (2) and converted into input audio signals (I1, I2), - wherein a first adaptive beamformer (28, 28a) with a variable first notch direction (N) is applied directly or indirectly to the input audio signals (I1, I2) to generate a first directionally attenuated audio signal (R) and wherein the first notch direction (N) is adjusted so that the energy content of the first directionally attenuated audio signal (R) is minimized, - wherein a second adaptive beamformer (28, 28b) with a variable second notch direction (N) is applied directly or indirectly to the input audio signals (I1, I2) to generate a second directionally attenuated audio signal (R) and wherein the second notch direction (N) is set to a value different from the first notch direction (N) so that the energy content of the second directionally attenuated audio signal (R) is minimized, - wherein the first notch direction (N) and the second notch direction (N) are evaluated comparatively, and wherein a head rotation of the user is recorded qualitatively and / or quantitatively if a correlated change in the first notch direction (N) and the second notch direction (N) is detected in the course of the comparative evaluation.

Description

[0001] The invention relates to a hearing system for supporting a user's hearing, comprising at least one hearing instrument worn on the head, particularly in or on one ear of the user. The invention further relates to a method for operating such a hearing system.

[0002] A hearing instrument is generally defined as an electronic device that supports the hearing of a person wearing the hearing instrument (hereinafter referred to as the "wearer" or "user"). In particular, the invention relates to hearing instruments designed to fully or partially compensate for the hearing loss of a hearing-impaired user. Such a hearing instrument is also referred to as a "hearing aid." There are also hearing instruments designed to protect or improve the hearing of users with normal hearing, for example, to enable improved speech comprehension in complex listening situations.

[0003] Hearing instruments in general, and hearing aids in particular, are usually designed to be worn on the user's head or ear, particularly as behind-the-ear devices (also known as BTE devices) or in-the-ear devices (also known as ITE devices). In terms of their internal structure, hearing instruments usually have at least one (acousto-electrical) input transducer, a signal processing unit (signal processor), and an output transducer. During operation of the hearing instrument, the or each input transducer receives airborne sound from the hearing instrument's environment and converts this airborne sound into an input audio signal (i.e., an electrical signal that conveys information about the ambient sound). This at least one input audio signal is also referred to below as the "recorded sound signal."In the signal processing unit, the or each input audio signal is processed (i.e., its sound information is modified) to support the user's hearing, in particular to compensate for a user's hearing loss. The signal processing unit outputs a correspondingly processed audio signal (also referred to as the "output audio signal" or "modified sound signal") to the output transducer.

[0004] In most cases, the output transducer is designed as an electro-acoustic transducer that converts the (electrical) output audio signal back into airborne sound, which is then emitted into the user's ear canal after being modified relative to the ambient sound. In a hearing instrument worn behind the ear, the output transducer, also known as the "receiver," is usually integrated outside the ear in a housing of the hearing instrument. In this case, the sound emitted by the output transducer is guided into the user's ear canal via a sound tube. Alternatively, the output transducer can be located in the ear canal, and thus outside the housing worn behind the ear. Such hearing instruments are also referred to as "receiver in canal" devices.Hearing instruments worn in the ear that are so small that they do not protrude beyond the ear canal are also called CIC devices (from the English term “completely in canal”).

[0005] In other designs, the output transducer can also be an electromechanical transducer that converts the output audio signal into structure-borne sound (vibrations), which is then transmitted, for example, to the user's skull. There are also implantable hearing instruments, particularly cochlear implants, and hearing instruments whose output transducers directly stimulate the user's auditory nerve.

[0006] The term "hearing system" refers to a single device or a group of devices and, where appropriate, non-physical functional units that together provide the functions required for the operation of a hearing instrument. In the simplest case, the hearing system may consist of a single hearing instrument. Alternatively, the hearing system may comprise two interacting hearing instruments to serve both ears of the user. In this case, it is referred to as a "binaural hearing system." Additionally or alternatively, the hearing system may comprise at least one other electronic device, for example, a remote control, a charger, or a programming device for the or each hearing aid.Modern hearing systems often feature a control program, particularly in the form of an app, instead of a remote control or dedicated programming device. This control program is designed for implementation on an external computer, particularly a smartphone or tablet. The external computer is usually not part of the hearing system itself, as it is usually provided independently of the hearing system and not by the hearing system manufacturer.

[0007] To attenuate background noise during operation of a hearing system, and thus in particular to improve speech intelligibility during communication between the user and another speaker, direction-dependent attenuation (beamforming) of the input audio signal is often used as part of the signal processing in a hearing system. In modern hearing systems, corresponding attenuation units (beamformers) are sometimes designed adaptively. Such an adaptive beamformer can regularly variably align a direction of maximum attenuation (notch) towards a specific noise source in order to attenuate the sound component emanating from this noise source particularly effectively. However, when the user turns their head, the notch of an adaptive beamformer should be adjusted in the opposite direction to the head rotation so that the beamformer remains aligned with the noise source to be attenuated, even during and after the head rotation.Otherwise, the direction-dependent attenuation when the head is turned leads to a modulation of the modified sound signal emitted by the hearing system to the user, which can sometimes seriously impair the user's hearing impression and, in extreme cases, can even cause a deterioration in speech comprehension (instead of the desired improvement).

[0008] To avoid such negative effects, an adaptive beamformer is often implemented with a sufficiently high adaptation speed so that it can automatically realign itself without any noticeable time delay when the head is turned. However, such fast-adapting beamformers tend to be unstable in dynamic listening situations. In particular, the notch of such a beamformer sometimes jumps back and forth between different interference sources, which in turn can significantly impair the user's hearing. Another approach is to detect head rotation and, in this case, adjust the beamformer as needed.

[0009] To detect head rotation, modern hearing instruments are often equipped with an accelerometer, a gyroscope, or an electronic compass. However, the integration of such a sensor increases the technical complexity and thus the manufacturing effort of a hearing instrument, and can be difficult or even impossible, especially in small hearing instruments.

[0010] DE 10 2019 201 879 B3 discloses a method for operating a hearing system having two input transducers and a signal processing device. In order to determine the activity of a lateral useful signal source in the environment of the hearing system, the two input transducers convert the acoustic signals incident on them into input signals. A filtered input signal is generated from these input signals using a direction-dependent notch filter unit. A measure of attenuation caused by the direction-dependent notch filter unit is determined from the filtered input signal and the input signal of at least one of the two input transducers. By comparing this (attenuation) measure with a reference, the presence or absence of activity of a lateral useful signal source is determined.

[0011] The application is based on the task of enabling a space-saving and comparatively inexpensive detection of a head rotation during operation of a hearing system.

[0012] With regard to a method, this object is achieved according to the invention by the features of claim 1. With regard to a hearing aid system, the object is achieved according to the invention by the features of claim 9. Advantageous and partly inventive embodiments or further developments of the invention are set out in the subclaims and the following description.

[0013] The invention is generally based on a hearing system for supporting the hearing of a user, wherein the hearing system has at least one hearing instrument worn on the head, in particular in or on one ear of the user. As described above, in simple embodiments of the invention the hearing system can consist exclusively of a single hearing instrument. In another embodiment of the invention the hearing system comprises, in addition to the hearing instrument, at least one further component, e.g. a further (in particular similar) hearing instrument for supplying the other ear of the user, a control program (in particular in the form of an app) for execution on an external computer (in particular a smartphone) of the user and / or at least one further electronic device, e.g. a remote control or a charger.In this case, the hearing instrument and the at least one other component exchange data with each other, with data storage and / or data processing functions of the hearing system being divided between the hearing instrument and the at least one other component.

[0014] The hearing system has at least two input transducers, each of which serves to receive a sound signal (particularly in the form of airborne sound) from the environment of the hearing instrument. The at least two input transducers can be arranged in the same hearing instrument, particularly if the hearing system comprises only a single hearing instrument. In a binaural hearing system with two hearing instruments, the at least two input transducers can alternatively be distributed between the two hearing instruments.

[0015] The hearing system expediently further comprises a signal processing unit for processing (modifying) the recorded sound signal to support the user's hearing, as well as an output transducer for outputting the modified sound signal. In a binaural hearing system, both hearing instruments preferably each have a signal processing unit and an output transducer. Instead of a second hearing instrument with an input transducer, signal processing unit, and output transducer, the hearing system for the second ear can, within the scope of the invention, also have a hearing instrument that does not have an output transducer itself, but only records sound and transmits it—with or without signal processing—to the hearing instrument of the first ear. Such so-called CROS or BiCROS instruments are used particularly for users with unilateral deafness.Furthermore, within the scope of the invention, the signal processing or a part thereof can also be outsourced from the hearing instrument or hearing instruments to an external unit, e.g. an app running on a smartphone.

[0016] The or each hearing instrument of the hearing system is, in particular, available in one of the designs described above (BTE device with internal or external output transducer, ITE device, e.g., CIC device, hearing implant, especially cochlear implant, hearable, etc.). In the case of a binaural hearing system, both hearing instruments are preferably designed in the same way.

[0017] Each of the input transducers is, in particular, an acousto-electrical transducer that converts ambient airborne sound into an electrical input audio signal. The or each output transducer is, if appropriate, preferably designed as an electro-acoustic transducer (earpiece), which in turn converts the audio signal modified by the signal processing unit into airborne sound. Alternatively, the output transducer is designed to emit structure-borne sound or to directly stimulate the user's auditory nerve.

[0018] According to the invention, multiple, direction-dependent attenuation of the input audio signals (or internal audio signals derived by pre-processing the input audio signals) is used by means of at least two adaptive beamformers to analyze the listening situation (in particular the position of dominant noise sources relative to the user's head) and thereby detect a turn of the user's head. In the course of the method, a sound signal from the user's surroundings is recorded by means of the at least two input transducers of the hearing system and converted into input audio signals. The input audio signals are fed directly (i.e. in unprocessed form) or indirectly (i.e. in already pre-processed form) to a first adaptive beamformer with a variable first notch direction and to a second beamformer with a second variable notch direction.

[0019] The first adaptive beamformer is applied (directly or indirectly) to the input audio signals to generate a first directionally attenuated audio signal. The first notch direction is adjusted to minimize the energy content of the first directionally attenuated audio signal. Similarly, the second adaptive beamformer is applied (directly or indirectly) to the input audio signals to generate a second directionally attenuated audio signal. The second notch direction is also adjusted to minimize the energy content of the second directionally attenuated audio signal. The two adaptive beamformers are coupled, so that the second notch direction can only assume a value different from the first notch direction. This prevents the two adaptive beamformers from aligning themselves to the same noise source.

[0020] In a preferred embodiment of the invention, the notch directions are defined in the form of angle specifications, for example, relative to the user's viewing direction. Alternatively, the notch directions can also be specified as abstracted quantities that are linearly or non-linearly correlated with the orientation of the notches, for example, in the form of a weighting factor used to weight various basic directional signals (e.g., a cardioid signal and an anti-cardioid signal, etc.) to adjust common adaptive beamformers, or in the form of a variable time delay with which different signal components are superimposed to generate the directional effect.

[0021] To detect head rotation, the first notch direction and the second notch direction are evaluated comparatively. The user's head rotation is recorded qualitatively and / or quantitatively if a correlated change in the first notch direction and the second notch direction is detected during the comparative evaluation.

[0022] The method is based on the realization that when the head is rotated—relative to the head and thus viewed from the position of at least one hearing instrument—all static noise sources in the user's environment appear to rotate synchronously and in the same way around the head, whereas such correlated rotation of noise sources is extremely unlikely when the head is stationary. By comparing the notch directions of different beamformers aimed at different noise sources with each other with regard to the correlation of the changes in the notch directions, changes attributable to a head rotation can be effectively distinguished from changes caused by an actual movement of noise sources. This allows head rotations to be detected. Advantageously, the method can be carried out using the signal processing means (in particular a signal processor) already present in a hearing system.In particular, the adaptive beamformers described above can be (and preferably are) implemented using software running in a signal processor of the hearing system. In this case, dedicated hardware is not required to implement the method and is preferably not provided. In any case, however, an acceleration, motion, or direction sensor is not required for the head rotation detection according to the invention and is therefore preferably not provided within the hearing system. The method according to the invention can therefore be implemented in the mass production of hearing systems with comparatively little effort and can also be used without problems in very small hearing instruments.

[0023] However, the method according to the invention can also be used in hearing systems in which head rotation detection is conventionally implemented using an acceleration, motion, or direction sensor. In this case, the method according to the invention is advantageous for determining head rotation redundantly and thus avoiding or correcting any detection errors in the sensor-based head rotation detection.

[0024] In particular, a matching duration and / or matching start and end times of the change are identified as indicators of a correlated change in the notch directions of the two adaptive beamformers. Additionally or alternatively, a matching rotation angle interval and / or a matching rotation rate of the notch directions are identified as indicators of a correlated change. In addition or alternatively, a correlated change in the notch directions is identified by forming the mathematical cross-correlation function.

[0025] In principle, in simple embodiments of the invention, it is possible for the head rotation to be detected only qualitatively. In this case, it is only detected that the head is being turned, but not how the head is being turned. For this purpose, for example, upon and during the detection of the head rotation, an indication signal indicating the head rotation (e.g., in the form of a so-called flag, i.e., a one-bit signal) is generated. Additionally or alternatively, the head rotation is detected qualitatively by detecting (and possibly storing) an associated time point.

[0026] In addition or alternatively to the qualitative detection, the head rotation is (optionally also) detected quantitatively in preferred embodiments of the invention. In this case, the type and / or extent of the head rotation is also detected. For this purpose, at least one measured variable is preferably detected that is characteristic of the rotation rate (angular velocity), a rotation angle interval, a duration of the head rotation (and additionally or alternatively the start and end times of the head rotation) and / or a time-dependent orientation of the head in the surrounding space. This measured variable can be the rotation rate (angular velocity), the rotation angle interval, the duration of the head rotation (or start and end times of the head rotation) and / or the time-dependent orientation of the head itself.However, the measured variable can also be an abstract quantity, for example, the rate of change, the change interval, or the start and end times of the change in the weighting factor described above or the time delay described above. Within the scope of the invention, the head rotation can be recorded either as a one-dimensional rotation of the head around the vertical axis or—in refined variants of the method—as a two- or three-dimensional rotation of the head in space.

[0027] In order to avoid detection errors (in particular a misinterpretation of moving noise sources as an indication of head rotation), in a preferred embodiment of the method, in addition to the first and second adaptive beamformers, at least one further (i.e., i-th with i = 3,4,5, ...) adaptive beamformer with a variable further (i-th with i = 3,4,5, ...) notch direction is applied directly or indirectly to the input audio signals in order to generate a further (i-th with i = 3,4,5, ...) direction-dependent attenuated audio signal. Like the second adaptive beamformer, the or each further (i-th) beamformer is coupled to the other beamformers, so that all beamformers have to adapt to different noise sources.The additional (i-th) notch direction—which is defined in the same way as the first and second notch directions as an angle specification or abstracted quantity—is therefore also set to a value different from the notch directions of the other beamformers, so that the energy content of the additional (i-th) directionally attenuated audio signal is minimized. In addition to the first and second notch directions, at least one additional (i-th) notch direction is also included in the comparative evaluation. A head rotation of the user is recorded qualitatively and / or quantitatively in the manner described above if a correlated change in at least two of the notch directions is detected during the comparative evaluation.Preferably, the number of beamformers is dynamically adjusted to the number of noise sources (at least the dominant noise sources, i.e. those noise sources that make a significant contribution to the ambient sound) during operation of the hearing system.

[0028] The correlated change of at least two notch directions is a necessary, but not necessarily sufficient, condition for detecting head rotation. Thus, in refined versions of the invention, the comparative evaluation of the notch directions can be supplemented by at least one additional condition to further reduce the risk of detection errors.

[0029] Such additional conditions specifically address the case where, under certain circumstances, at least one of the coupled beamformers can no longer find any dominant sound sources to which it could align itself in simple listening situations. Due to the lack of alignment to a dominant sound source, the notch direction of such a beamformer regularly exhibits unstable temporal behavior (and thus wanders around the room almost randomly). Under unfavorable circumstances, this can lead to a random correlation with the notch direction of another beamformer aligned to a moving sound source, thus causing a detection error.

[0030] In order to exclude such detection errors, in advantageous embodiments of the method unstable notch directions are detected and excluded from the comparative evaluation or at least considered with less weight.

[0031] Preferably, at least one of the notch directions is considered in the comparative evaluation with different (binary or continuous) weighting depending on the strength of the energy minimization achieved by varying this notch direction—and thus depending on the strength of the sound source toward which the corresponding beamformer is aimed. Beamformers that do not find a distinct energy minimum are considered less or not at all in the comparative evaluation.

[0032] Additionally or alternatively, at least one of the notch directions is taken into account in the comparative analysis depending on the temporal stability of this notch direction with different (binary or continuous) weighting. Notch directions that have varied comparatively strongly in a previous time period are taken into account to a lesser extent or not at all. The temporal stability of the notch direction is determined, for example, by recording the standard deviation and / or the mean crossing rate of the notch direction for a given past period. The mean crossing rate is the rate at which the current notch direction exceeds or falls below a moving temporal average of the notch direction. Additionally or alternatively, the number of sign changes in the first temporal derivative of the notch direction is used as a measure of the temporal stability of the notch direction.

[0033] In a practical embodiment, the hearing system comprises, as a functional component of the signal processing, a signal processing unit to which the input audio signals are fed directly or indirectly via a preprocessing stage and in which these audio signals are modified by means of a number of signal processing processes (i.e., at least one signal processing process, but preferably a plurality of signal processing processes) depending on a number of adjustable signal processing parameters (i.e., at least one signal processing parameter, but preferably a plurality of signal processing parameters) in order to be output to the user by means of an output transducer of the hearing instrument. Preferably, at least one signal processing parameter is adjusted depending on the qualitative and / or quantitative detection of the head rotation.

[0034] The signal processing unit preferably comprises at least one adaptive signal processing process, e.g., for direction-dependent attenuation (adaptive beamforming), for feedback cancellation (adaptive feedback cancellation), for active noise cancellation, etc., by which the input audio signals or an intermediate signal derived therefrom through preprocessing are modified depending on an adjustable adaptation speed. In this case, the adaptation speed is preferably adjusted depending on the qualitative and / or quantitative detection of the head rotation. For example, the adaptation speed is increased if and as long as a head rotation is detected by means of the method according to the invention.

[0035] Additionally or alternatively, the recording of head rotation according to the method can also be used for other purposes, e.g. for documentation purposes (data logging), for recording operating commands from the user to enable the user to control the hearing system by gestures (namely targeted head movements), or for evaluating the physiological or psychological state of the user (for example, by recording and statistically evaluating the user's head movement, conclusions can be drawn about physiological disorders such as dizziness or psychological limitations).

[0036] At least one of the adaptive beamformers used to detect head rotation according to the method can be a component of the signal processing unit within the scope of the invention. In this case, the directionally attenuated signal generated by this beamformer is also output to the user as a modified audio signal or part of it—possibly in further processed form and / or combined with other signal components.

[0037] In a preferred embodiment of the invention, however, the adaptive beamformers used to detect head rotation are used exclusively for analyzing the listening situation. In this case, the adaptive beamformers are part of a signal analysis unit separate from the signal processing unit. The directionally attenuated signal generated by the beamformers is used exclusively for determining energy optimization and thus for adjusting the notch direction.

[0038] To detect head rotation within the method, beamformers are preferably used that, on the one hand, adapt sufficiently quickly to be able to follow a normal head rotation in real time. On the other hand, it is preferable to prevent the beamformers from jumping back and forth between different noise sources in dynamic listening situations. For this purpose, in an advantageous method variant, the adaptation speed of the beamformers is varied depending on the strength of the energy minimization.As long as a particular beamformer is directed toward an active noise source and the energy minimization for the set notch direction is sufficiently large (which can be recognized, for example, by the ratio of the energy content of the directionally attenuated audio signal to the energy content of the audio signals fed to the beamformer falling below a predetermined limit), the adaptation speed for this beamformer is set to a comparatively high value. The limit is preferably varied depending on the type of acoustic scene. In a diffuse sound field, for example, the limit is selected to be lower than in a quiet environment with few sound sources, since experience has shown that the attenuation effect of the beamformer is less in the former case than in the latter.For example, the adaptation speed is set to allow a change in the notch direction of up to 180° per second. Otherwise, especially if the noise source to which the beamformer is directed has temporarily become inactive, thus reducing the strength of energy minimization, particularly if it falls below the threshold, the adaptation speed is reduced. For example, in this case, the permissible rate of change of the notch direction is limited to ± 2° per second. This reduction in the adaptation speed ensures that the beamformers maintain their alignment to a specific noise source even if that noise source becomes temporarily inactive.

[0039] When a head rotation is detected by the method, the notch direction of the or each beamformer directed toward a currently inactive noise source is preferably also adjusted to the correlated changes in the notch directions of the other beamformers directed toward active noise sources. This ensures that the adjusted notch direction remains aligned with the associated noise source even if a head rotation is detected, even if the associated noise source is temporarily inactive, so that this beamformer can be used again immediately for head rotation detection as soon as the noise source becomes active again.

[0040] The hearing system according to the invention is generally configured to automatically carry out the above-described method according to the invention. For this purpose, the hearing system comprises the first and second adaptive beamformers (as described above). The hearing system further comprises an evaluation unit configured to comparatively evaluate the first notch direction and the second notch direction and to qualitatively and / or quantitatively detect a head rotation of the user if, during the comparative evaluation, it detects a correlated change in the first notch direction and the second notch direction.

[0041] The hearing system's device for automatically implementing the method according to the invention is of a programming and / or circuitry nature. The hearing system according to the invention therefore comprises programming means (software) and / or circuitry means (hardware, e.g., in the form of an ASIC) that automatically implement the method according to the invention during operation of the hearing system. The programming or circuitry means for implementing the method, in particular the beamformers and the evaluation unit, can be arranged exclusively in the hearing instrument (or instruments) of the hearing system. Alternatively, the programming or circuitry means for implementing the method are distributed across the hearing instrument(s) and at least one other device or software component of the hearing system.For example, the programming means for implementing the method are distributed between at least one hearing instrument of the hearing system and a control program installed on an external electronic device (in particular, a smartphone). As mentioned above, the external electronic device itself is generally not part of the hearing system.

[0042] The above-described embodiments of the method according to the invention correspond to corresponding embodiments of the hearing system according to the invention. The above statements regarding the method according to the invention can be applied accordingly to the hearing system according to the invention, and vice versa.

[0043] In preferred embodiments of the invention, the evaluation unit is particularly designed to - to qualitatively record the head rotation by generating an indication signal indicating the head rotation (e.g. setting a flag) and / or recording the time of the head rotation and / or - for the quantitative recording of head rotation, to record a measurement variable characteristic of a rotation rate (angular velocity), a rotation angle interval, a duration of head rotation and / or an orientation of the head in the surrounding space.

[0044] Preferably, the hearing system comprises at least one further (i-th) adaptive beamformer (as described above) in addition to the first and second beamformers. The evaluation unit is configured to comparatively evaluate the first notch direction, the second notch direction, and the at least one further notch direction, and to qualitatively and / or quantitatively detect a head rotation of the user if a correlated change in at least two of the notch directions is detected during the comparative evaluation.

[0045] The evaluation unit is further preferably configured to evaluate at least one of the notch directions in the comparative evaluation • depending on the strength of the energy minimization achieved by varying this notch direction and / or • depending on the time stability of this notch direction with different (binary or continuous) weighting.

[0046] The at least one hearing instrument expediently has a signal processing unit to which the input audio signals are fed directly or indirectly via a preprocessing unit. In this unit, these audio signals are processed by means of a number of signal processing processes depending on a number of adjustable signal processing parameters in order to be output to the user via an output transducer of the hearing instrument. The hearing system preferably has means (e.g., the evaluation unit or a separate parameterization unit) for adjusting at least one signal processing parameter depending on the qualitative and / or quantitative detection of the head rotation.

[0047] The signal processing unit preferably comprises at least one adaptive signal processing process (as described above), which is parameterized by an adjustable adaptation speed. The hearing system preferably comprises means (again, e.g., the evaluation unit or a separate parameterization unit) for adjusting this adaptation speed depending on the qualitative and / or quantitative detection of the head rotation.

[0048] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings: Fig. 1 shows a schematic representation of a hearing system consisting of a single hearing instrument in the form of a hearing aid worn behind the ear of a user, Fig. 2 shows in a schematic block diagram the structure of a signal processing unit of the hearing instrument Fig. 1, and Fig. 3 in representation according to Fig. 1 an alternative embodiment of the hearing system, in which it comprises a hearing instrument in the form of a hearing aid that can be worn behind the ear and a control program (“hearing app”) implemented in a smartphone.

[0049] Corresponding parts and sizes are always provided with the same reference symbols in all figures.

[0050] Fig. Figure 1 shows a hearing system 2, which here consists of a single hearing aid 4, i.e., a hearing instrument designed to support the hearing of a hearing-impaired user. In the example shown here, the hearing aid 4 is a BTE hearing aid worn behind the user's ear.

[0051] Optionally, in a further embodiment of the invention, the hearing system 2 comprises a second hearing aid (not expressly shown) for supplying the second ear of the user, which in terms of its construction is particularly similar to the one shown in Fig. 1 corresponds to the hearing aid 4 shown.

[0052] Within a housing 5, the hearing aid 4 comprises two microphones 6 as input transducers and a receiver 8 as output transducer. The hearing aid 4 further comprises a battery 10 and signal processing in the form of a signal processor 12. Preferably, the signal processor 12 comprises both a programmable subunit (e.g., a microprocessor) and a non-programmable subunit (e.g., an ASIC).

[0053] The signal processor 12 is supplied with an electrical supply voltage U from the battery 10.

[0054] During normal operation of the hearing aid 4, the microphones 6 each pick up airborne sound from the environment of the hearing aid 4. The microphones 6 convert the sound into an (input) audio signal I1 or I2, respectively, which contains information about the recorded sound. The input audio signals I1, I2 are fed within the hearing aid 4 to the signal processor 12, which modifies these input audio signals I1, I2 to support the user's hearing.

[0055] The signal processor 12 outputs an output audio signal O, which contains information about the processed and thus modified sound, to the listener 8.

[0056] The receiver 8 converts the output sound signal O into a modified airborne sound. This modified airborne sound is transmitted into the user's ear canal via a sound channel 14, which connects the receiver 8 to a tip 16 of the housing 5, and via a flexible sound tube (not explicitly shown) that connects the tip 16 to an earpiece inserted into the user's ear canal.

[0057] The structure of the signal processing is in Fig. 2 in more detail. This shows that the signal processing of the hearing system 2 is divided into two functional components, namely a signal processing unit 18 and a signal analysis unit 20. The signal processing unit 18 serves to generate the output audio signal O from the input audio signals I1, I2 of the microphones 6 or from internal audio signals I1', I2' derived therefrom by preprocessing. In the former case, the input audio signals I1, I2 of the microphones 6 are fed directly to the signal processing unit 18. In the latter case, which is exemplified in Fig. 2, the input audio signals I1, I2 of the microphones 6 are first fed to a preprocessing unit 22, which then derives the internal audio signals I1', I2 and feeds them to the signal processing unit 18.

[0058] In the preprocessing unit 22, the input audio signals I1, I2 are preferably superimposed on one another with a time delay to form the internal audio signals I1', I2', so that the two internal audio signals I1', I2' correspond to a cardioid signal and an anti-cardioid signal, respectively.

[0059] The signal processing unit 18 comprises a number of signal processing processes 24 which process the input audio signals I or - in the example according to Fig. 2 - successively process and modify the internal audio signals I1', I2 to generate the output audio signal O, thus compensating the user's hearing loss.

[0060] The signal processing processes 24 include, for example, - a process for noise and / or feedback suppression, - a process for dynamic compression and - a process for frequency-dependent amplification based on audiogram data, - etc.

[0061] At least one signal processing parameter P is assigned to at least one of these signal processing processes 24 (usually all signal processing processes 24 or at least most signal processing processes 24). The or each signal processing process 24 is a one-dimensional variable (binary variable, natural number, floating-point number, etc.) or a multi-dimensional variable (array, function, etc.) whose value parameters (i.e., influences) the functionality of the respectively assigned signal processing process 24. Signal processing parameters P can switch the respectively assigned signal processing process 24 on or off, continuously or gradually amplify or attenuate the effect of the respectively assigned signal processing process 24, define time constants for the respective signal processing process 24, etc.

[0062] For example, the signal conditioning parameters P - Gain factors for a frequency-dependent amplification process, - a characteristic curve for a dynamic compression process, - a control variable for continuously adjusting the strength of a noise or feedback suppression process, - etc.

[0063] Preferably, at least one of the signal processing processes 24 is an adaptive process whose adaptation speed can be variably adjusted using one of the signal processing parameters P. For example, the signal processing processes 24 comprise an adaptive "beamformer" with a variable adaptation speed, which is configured to attenuate the input audio signals I1, I2 (or the internal audio signals I1', I2' derived therefrom) in a direction-dependent manner to generate the output audio signal O.

[0064] The signal conditioning processes 24 are implemented, for example, partly in the form of (non-programmable) hardware circuits and partly in the form of software modules (in particular firmware) in the signal processor 12.

[0065] The signal analysis unit 20 comprises - preferably in addition to other functions for sound analysis not explicitly shown here, such as a classifier for analyzing listening situations - a head rotation detection unit 26, which is preferably implemented in the form of software in the signal processor 12. The head rotation detection unit 26 comprises several beamformers 28 of the same design, i.e. processes for direction-dependent attenuation, to which the input signals I1, I2 or - as in the example according to Fig. 2 - the derived internal audio signals I1', I2' - are fed to the beamformer 28, and each outputs a direction-dependent attenuated audio signal R. Each beamformer 28 generates the associated direction-dependent attenuated signal R by combining the two supplied audio signals I1', I2' (in the example according to Fig. 2 i.e. a cardioid signal and an anti-cardioid signal) are superimposed on each other weighted with a weighting factor a: R=I1'−a⋅I2' with a=[−1;1]

[0066] The weighting factor a determines the value of a notch direction N, which—relative to the user's head—indicates the direction in which the respective beamformer 28 maximally attenuates the supplied audio signals I1', I2'. The weighting factor a and the notch direction are uniquely correlated via a non-linear mathematical function (N = N(a)) and can thus be converted into one another.

[0067] The beamformers 28 (in the example according to Fig. 2 (three beamformers 28a, 28b, and 28c) are each adaptively configured. Each beamformer 28 is configured to automatically adjust the weighting factor a (and thus the notch direction N) such that the energy content of the directionally attenuated audio signal R output by it is minimized. The directionally attenuated audio signal R is thus a function of the weighting factor a (R = R(a)), or, equivalently, a function of the notch direction N (R = R(N)).

[0068] For this purpose, the directionally attenuated signal R output by each beamformer 28 is fed back. As a measure for energy minimization and thus for setting the weighting factor a (and thus the notch direction N), each beamformer 28 determines, for example, the ratio of the squared levels of the directionally attenuated audio signal R and the internal audio signals I1', I2', ER=|R(a)|20.5⋅(|I1'|2+|I2'|2) and minimizes this quantity, for example, using the Newton method, by varying the weighting factor a. As an alternative to the Newton method, the conjugate gradient method (CG method) is used.

[0069] In the example according to Fig. 2, the beamformers 28 serve exclusively for analyzing the input audio signals I1, I2 or the internal audio signals I1', I2'. The directionally attenuated audio signals R of these beamformers 28 are therefore not output via the earpiece 8 or further processed for output.

[0070] From the weighting factor a, each beamformer 28 calculates the corresponding notch direction N and outputs this notch direction N to a downstream evaluation unit 30. In addition, each beamformer 28 also outputs the notch direction N it has set to a possibly subordinate beamformer 28. Thus, the beamformer 28a outputs according to Fig. 2 outputs its set notch direction N to beamformers 28b and 28c, while beamformer 28b outputs its set notch direction N to beamformer 28c. Each of the beamformers 28 is configured such that it omits the notch directions N supplied to it from the higher-level beamformers 28 (each observing a spacing interval of, for example, ±5°) when setting its own notch direction N. The beamformers 28a, 28b, 28c thus form a cascade of interconnected beamformers 28, in which each of the beamformers 28 is forced to set a different notch direction N and thus aligns itself with a different noise source.

[0071] The evaluation unit 30 compares the temporal progression of the supplied notch directions N with each other. As soon as the evaluation unit 30 detects a correlated change in at least two of the supplied notch directions N, the evaluation unit 30 recognizes this as an indication that the user has moved their head. In this case, the evaluation unit 30 generates an indication signal D indicating the head rotation and feeds this indication signal D to the signal processing unit 18.

[0072] Within the signal processing unit 18, the indication signal D is fed to a parameterization unit 32, which provides the signal processing parameters P to the signal processing processes 24. The parameterization unit 32 specifies at least one of the signal processing parameters P with a value that varies depending on the indication signal D. Thus, the parameterization unit 32 controls at least one of the signal processing processes 24 in a different manner when a head rotation is detected by the head rotation detection unit 26 than during periods in which the head rotation detection unit 26 does not detect any head rotation. If the signal processing processes 24 comprise an adaptive process, in particular an adaptive beamformer, with a variable adaptation speed, this adaptation speed is preferably varied by the parameterization unit 32 depending on the indication signal D.In particular, the parameterization unit 32 increases the adaptation speed during and shortly after the head rotation, so that the adaptive process can quickly adapt to the change in the hearing situation caused by the head rotation. In periods in which the head rotation detection unit 26 does not detect a head rotation, the adaptation speed is reduced by the parameterization unit 32 to a comparatively low value. The adaptive signal processing process is thus set to be comparatively slow in the absence of a head rotation to ensure stable signal processing.In addition or alternatively to increasing the adaptation speed, the parameterization unit 32 temporarily reduces the strength of the directivity (in particular the notch depth) during and shortly after the detected head rotation, thereby avoiding signal processing artifacts and enabling better orientation of the hearing aid wearer.

[0073] To detect correlated changes in at least two of the supplied notch directions N, the evaluation unit 30 forms the cross-correlation function pairwise between the supplied notch directions N. In this case, the evaluation unit 30 detects the presence of a head rotation if the value of at least one of the formed cross-correlation functions exceeds a predetermined threshold.

[0074] In an alternative embodiment, the evaluation unit 30 records the start and end times of changes as well as the respective change amplitude (i.e. the value by which the respective notch direction N has changed) for each of the supplied notch directions N. In this case, it detects the presence of a head rotation if at least two of the supplied notch directions N each have a change with (within predetermined tolerance ranges) the same start and end times and the same change amplitude.

[0075] Alternatively, the evaluation unit 30 detects the sign and / or the magnitude of the temporal change (in particular, the sign of the first temporal derivative) for each of the supplied notch directions N. In this case, it detects the presence of a head rotation if a sufficiently large number of the determined signs are the same (e.g., if all notch directions N change in the same direction, except for the notch direction N of a beamformer 28 that adapts to the user's own voice) or if several notch directions N experience a change of the same magnitude.

[0076] In both cases, however, the evaluation unit 30 only generates the indication signal D upon detection of a head rotation when the change in the correlated notch directions N exceeds a predetermined threshold value, for example 10° (i.e. when the correlated notch directions N have changed by more than the predetermined threshold value).

[0077] In a simple embodiment of the hearing system 2, the indication signal D is a quantity that merely qualitatively indicates the detected head rotation, without further characterizing this head rotation. For example, the evaluation unit 30 sets a flag as the indication signal D as soon as and as long as it detects a head rotation.

[0078] In addition or alternatively to the purely qualitative indication of the head rotation, the indication signal D preferably contains at least one item of information that qualitatively characterizes the detected head rotation, in particular an item of information on the angle of rotation by which the head is rotated and / or on the rate of rotation (i.e. the angular velocity) of the head rotation.

[0079] In order to ensure that each beamformer 28 can adapt its notch direction R in real time during a head rotation, but at the same time to avoid the notch direction N jumping back and forth between different noise sources, each beamformer 28 is preferably configured to adapt its adaptation speed depending on the strength of the energy minimization, in particular depending on the value of the quantity E R according to Eq. 2. As long as a particular beamformer 28 is directed towards an active noise source and thus the energy minimization for the set notch direction N is sufficiently large (for example, if and as long as the quantity E Rfalls below a predetermined limit), this beamformer 28 sets its adaptation speed to a comparatively high value so that, for example, a rate of change of the notch direction N of up to 180° per second is possible. Otherwise, i.e. if significant energy minimization cannot be achieved temporarily by varying the weighting factor a (and thus the notch direction N), the or each affected beamformer 28 reduces its adaptation speed so that, for example, the permissible rate of change of the notch direction is limited to ± 2° per second. This reduction in the adaptation speed ensures that the beamformers 28 maintain their orientation towards a specific noise source even if this noise source becomes briefly inactive.

[0080] Beamformers 28 which do not achieve significant energy minimization as described above (for example, because they are not yet or no longer aligned with a dominant noise source or because their associated noise source has become temporarily inactive) are referred to below as “searching” for linguistic simplification.

[0081] In order to prevent such a searching beamformer 28 from interfering with the comparative evaluation of the notch directions N carried out by the evaluation unit 30, the beamformers 28 are preferably configured to output the set notch direction N to the evaluation unit 30 and the downstream beamformers 28 only when they have aligned themselves with an active, dominant noise source and are therefore no longer searching.

[0082] In order to ensure that the head rotation detection unit 26 adapts to changing hearing situations and, in particular, that only the notch directions N of those beamformers 28 that are aligned with a dominant and long-term active noise source are taken into account by the evaluation unit 30, the beamformers 28 are, in a preferred embodiment of the hearing system 2, dynamically generated (activated) and, if necessary, terminated (deactivated) during operation of the hearing system 2 (for example, as objects of the same class in terms of software).

[0083] For example, the head rotation detection unit 26 generates a new beamformer 28 at regular intervals (e.g., every 60 seconds) and integrates it at the very bottom of the cascade of coupled beamformers 28.

[0084] If one of the beamformers 28 is continuously searching for a given period of time (for example, 40 seconds) and thus cannot achieve significant energy minimization (in particular if the size E R permanently falls below the limit value for the specified period of time), this beamformer 28 deactivates itself automatically and is thus removed from the cascade of coupled beamformers 28.

[0085] The automatic activation and deactivation of the beamformers 28 described above ensures that the number of beamformers 28 (active within the head rotation detection unit 26) is regularly adjusted to the number of dominant noise sources in the user's environment. However, to avoid numerical overload of the signal processor 12, the number of simultaneously active beamformers 28 is preferably limited to a predetermined maximum number, e.g., five beamformers 28.

[0086] In a variant of the hearing system 2 not explicitly shown, the evaluation unit 30 interacts with the beamformers 30 by initiating an adjustment of the notch direction N of the or each searching beamformer 28 by the angle of the detected head rotation upon detection of a head rotation. Thus, during a head rotation, the beamformers 28 remain aligned with their associated noise source even if the noise source was briefly inactive during the head rotation. The beamformer 28 can thus be used again immediately during and after the head rotation as soon as the noise source becomes active again.

[0087] Fig. Figure 3 shows a further embodiment of the hearing system 2, in which it comprises, in addition to the hearing aid 4 (or two hearing aids of this type for supplying both ears of the user), control software. This control software is referred to below as hearing app 40. The hearing app 40 is in the Fig. 3, the smartphone 42 is installed on a smartphone 42. The smartphone 42 itself is not part of the hearing system 2. Rather, the smartphone 42 is used by the hearing app 40 merely as a resource for storage space and computing power.

[0088] During operation of the hearing system 2, the hearing aid 4 and the hearing app 42 exchange data via a wireless data transmission connection 44. The data transmission connection 44 is based, for example, on the Bluetooth standard. The hearing app 42 accesses a Bluetooth transceiver of the smartphone 42 to receive data from the hearing aid 4 and to send data to it. The hearing aid 4, in turn, includes a Bluetooth transceiver (not explicitly shown) to send data to the hearing app 40 and to receive data from this app.

[0089] In the execution according to Fig. 3 are parts of the documents required for the implementation of the procedure in accordance with Fig. 2 required software components are not implemented in the signal processor 12, but rather in the hearing app 40. For example, in the embodiment according to Fig. 3 the evaluation unit 30 is implemented in the hearing app 40.

[0090] The invention is particularly clear from the exemplary embodiments described above, but is not limited to these exemplary embodiments. Rather, further embodiments of the invention can be derived by those skilled in the art from the claims and the above description. List of reference symbols 2 hearing system 4 Hearing aid 5 housings 6 Microphone 8 listeners 10 Battery 12 Signal processor 14 sound channel 16 lace 18 Signal processing unit 20 Signal analysis unit 22 Preprocessing unit 24 Signal processing process 26 Head rotation detection unit 28 beamformers 28a-28c Beamformer 30 evaluation unit 32 Parameterization unit 40 listening apps 42 smartphones 44 Data transmission connection a weighting factor D Information signal I1, I2 input audio signal I1', I2' (internal) audio signal N Notch direction O Output audio signal P Signal conditioning parameters R (directionally attenuated) audio signal U supply voltage

Claims

[1] Method for operating a hearing system (2) for supporting the hearing of a user, with at least one hearing instrument (4) worn on the head, in particular in or on an ear of the user, - wherein a sound signal from the user's environment is recorded by means of at least two input transducers (6) of the hearing system (2) and converted into input audio signals (I1, I2), - wherein a first adaptive beamformer (28, 28a) with a variable first notch direction (N) is applied directly or indirectly to the input audio signals (I1, I2) to generate a first direction-dependent attenuated audio signal (R), and wherein the first notch direction (N) is adjusted so that the energy content of the first direction-dependent attenuated audio signal (R) is minimized, - wherein a second adaptive beamformer (28, 28b) with a variable second notch direction (N) is applied directly or indirectly to the input audio signals (I1, I2) to generate a second directionally attenuated audio signal (R), and wherein the second notch direction (N) is set to a value different from the first notch direction (N) so that the energy content of the second directionally attenuated audio signal (R) is minimized, - wherein the first notch direction (N) and the second notch direction (N) are evaluated comparatively, and wherein a head rotation of the user is recorded qualitatively and / or quantitatively if a correlated change in the first notch direction (N) and the second notch direction (N) is detected in the course of the comparative evaluation. [2] Method according to claim 1, wherein for the qualitative detection of the head rotation an indication signal (D) indicating the head rotation is generated and / or the time of the head rotation is detected. [3] Method according to claim 1 or 2, wherein for the quantitative detection of the head rotation a measurement variable characteristic of a rotation rate, a rotation angle interval, a duration of the head rotation and / or an orientation of the head in the surrounding space is detected. [4] Method according to one of claims 1 to 3, - wherein at least one further adaptive beamformer (28, 28c) with a variable further notch direction (N) is applied directly or indirectly to the input audio signals (I1, I2) in order to generate a further direction-dependent attenuated audio signal (R), and wherein the further notch direction (N) is set to a value different from the notch directions (N) of the other beamformers (28, 28a, 28b), so that the energy content of the further direction-dependent attenuated audio signal (R) is minimized, - wherein the first notch direction (N), the second notch direction (N) and the at least one further notch direction (N) are comparatively evaluated, and wherein a head rotation of the user is qualitatively and / or quantitatively recorded if a correlated change in at least two of the notch directions (N) is detected in the course of the comparative evaluation. [5] Method according to one of claims 1 to 4, wherein at least one of the notch directions (N) is taken into account in the comparative evaluation with different weighting depending on the strength of the energy minimization achieved by the variation of this notch direction. [6] Method according to one of claims 1 to 5, wherein at least one of the notch directions (N) is taken into account in the comparative evaluation with different weighting depending on the time stability of this notch direction (N). [7] Method according to one of claims 1 to 6, wherein the input audio signals (I1, I2) are modified directly or indirectly in a signal processing unit (18) of the at least one hearing instrument (4) by means of a number of signal processing processes (24) depending on a number of adjustable signal processing parameters (P) in order to be output to the user by means of an output transducer (8) of the hearing instrument (4), and wherein at least one signal processing parameter (P) is set depending on the qualitative and / or quantitative detection of the head rotation. [8] Method according to one of claims 1 to 6, wherein the input audio signals (I1, I2) are modified directly or indirectly in a signal processing unit (18) of the at least one hearing instrument (4) by means of at least one adaptive signal processing process (24) as a function of an adjustable adaptation speed in order to be output to the user by means of an output transducer (8) of the hearing instrument (4), and wherein the adaptation speed is set as a function of the qualitative and / or quantitative detection of the head rotation. [9] Hearing system (2) for supporting the hearing of a user, with at least one hearing instrument (4) worn on the head, in particular in or on one ear of the user, - wherein the hearing system (2) comprises at least two input transducers (6) for receiving a sound signal from an environment of the user and for converting this sound signal into input audio signals (I1, I2), - wherein the hearing system (2) comprises a first adaptive beamformer (28, 28a) with a variable first notch direction (N), to which the input audio signals (I1, I2) are fed directly or indirectly, wherein the first adaptive beamformer (28, 28a) is configured to generate a first direction-dependent attenuated audio signal (R) and to adjust the first notch direction (N) so that the energy content of the first direction-dependent attenuated audio signal (R) is minimized, - wherein the hearing system (2) comprises a second adaptive beamformer (28, 28b) with a variable second notch direction (N), to which the input audio signals (I1, I2) are fed directly or indirectly, wherein the second adaptive beamformer (28, 28b) is configured to generate a second directionally attenuated audio signal (R) and to adjust the second notch direction (N) so that the energy content of the second directionally attenuated audio signal (R) is minimized, - wherein the hearing system (2) comprises an evaluation unit (30) which is configured to comparatively evaluate the first notch direction (N) and the second notch direction (N) and to qualitatively and / or quantitatively detect a head rotation of the user if, in the course of the comparative evaluation, it detects a correlated change in the first notch direction (N) and the second notch direction (N). [10] Hearing system (2) according to claim 9, wherein the evaluation unit (30) is configured to generate an indication signal (D) indicating the head rotation for the qualitative detection of the head rotation and / or to detect the time of the head rotation. [11] Hearing system (2) according to claim 9 or 10, wherein the evaluation unit (30) is configured to detect a variable characteristic of a rotation rate, a rotation angle interval, a duration of the head rotation and / or an orientation of the head in the surrounding space for the quantitative detection of the head rotation. [12] Hearing system (2) according to one of claims 9 to 11, - wherein the hearing system (2) comprises at least one further adaptive beamformer (28, 28c) with a variable further notch direction (N), to which the input audio signals (I1, I2) are fed directly or indirectly, wherein the further adaptive beamformer (28, 28c) is configured to generate a further direction-dependent attenuated audio signal (R) and to set the further notch direction (N) to a value different from the notch directions (N) of the other beamformers (28, 28a, 28b), so that the energy content of the further direction-dependent attenuated audio signal (R) is minimized, - wherein the evaluation unit (30) is configured to comparatively evaluate the first notch direction (N), the second notch direction (N) and the at least one further notch direction (N), and to qualitatively and / or quantitatively detect a head rotation of the user if a correlated change in at least two of the notch directions (N) is detected in the course of the comparative evaluation. [13] Hearing system (2) according to one of claims 9 to 12, wherein the evaluation unit (30) is configured to take into account at least one of the notch directions (N) in the comparative evaluation with different weighting depending on the strength of the energy minimization achieved by the variation of this notch direction (N). [14] Hearing system (2) according to one of claims 9 to 13, wherein the evaluation unit (30) is configured to take into account at least one of the notch directions (N) in the comparative evaluation with different weighting depending on the time stability of this notch direction (N). [15] Hearing system (2) according to one of claims 9 to 14, wherein the at least one hearing instrument (4) has a signal processing unit (18) which is designed to modify the input audio signals (I1, I2) or audio signals (I1', I2') derived therefrom by means of a number of signal processing processes (24) depending on a number of adjustable signal processing parameters (P) in order to be output to the user by means of an output transducer (8) of the hearing instrument (4), and wherein the hearing system (2) has means for setting at least one signal processing parameter (P) depending on the qualitative and / or quantitative detection of the head rotation. [16] Hearing system (2) according to one of claims 9 to 14, wherein the at least one hearing instrument (4) has a signal processing unit (18) which is designed to modify the input audio signals (I1, I2) or audio signals (I1', I2') derived therefrom by means of at least one adaptive signal processing process (24) as a function of an adjustable adaptation speed in order to be output to the user by means of an output transducer (8) of the hearing instrument (4), and wherein the hearing system (2) has means for adjusting the adaptation speed as a function of the qualitative and / or quantitative detection of the head rotation.

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